Linewidth enhancement factor and near-field pattern in tunnel injection In 0.4 Ga 0.6 As self-assembled quantum dot lasers

Measurements of ultra-low linewidth enhancement factor in ridge-waveguide tunnel injection In0.4Ga0.6As/GaAs self-assembled quantum dot lasers have been made and the results compared with similar quantum well lasers. Values of α∼3.8 were measured in the quantum well lasers, and α was ≤0.7 in the quantum dot lasers. The consequent suppression of filamentation in the quantum dot devices has also been observed.